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29, 1967 K. A. OESTERH ELD DEVICE FOR DRESSING CRUDE ASBESTOS FiledMarch 5, 1964 2 Sheets-Sheet 1 W n/rap KARL A. Gamma 40 g- 1967 K. A.OESTERHELD 3,337,922

DEVICE FOR DRESSING CRUDE ASBESTOS Filed March 5, 1964 2 Sheets-Sheet 2xwj /NVE/VTOE KflRL r4. OESTERHELD ya m ATTY

United States Patent 0 9,279 8 Claims. or. 19-66) This invention relatesto a device for dressing the bunch-like adhered asbestos natural statefibres separated from the source rock, in which the fibre bunchessuspended in a liquid are passed between friction surfaces under high,controllable hydraulic pressure so that the fibres are bent to and froin constantly varying directions and thereby the fibre bunches areopened up. For carrying out this method a device has become known inwhich a narrow passage gap is defined between a rigid shaft rotatablymounted in a cylindrical housing provided with an elastic lining, andthe housing surrounding the shaft, which gap is of equal width allthrough or in which narrow and wide passage gap sections alternate witheach other. Further it has been suggested to mount a conical drum on theshaft and to devise at least the outer cone shell thereof so as to beresilient or to provide the inner surface of the tapered housing with aresilient lining so that between the conical drum and the inner wall ofthe housing there is available a narrow passage gap of equal width allthrough, which lies on the conical surface of a frustum.

Bending the fibres to and fro in constantly varying direction representsa fulling action which has proved very advantageous for completelydressing the bunch-like adhered asbestos natural state fibres at thesame time avoiding injury to the fibres.

It is the object of the present invention to produce a dressing deviceof the specified type which has an improved fulling capacity and thus anincreased fibre dressing capacity.

The invention provides a device for dressing adhered asbestos naturalstate fibres separated from the source rock and suspended, in a liquid,of the type including a housing closed at least at one end by a cover,and a drum rotatably mounted within said housing by means of a drumshaft so as to define an annular passage between said drum and saidhousing surrounding said drum, said passage being adapted to receivesaid fibres suspended in the liquid to form a fibre-liquid mixtureforced through said passage under controllable hydraulic pressure andrepeated bending of said fibres to and fro in constantly varyingdirections, characterized in that said housing and said drum are ofcylindrical shape, said cylindrical drum has two circular end walls, aneccentric bore is provided in either of said circular end walls of saidcylindrical drum, a hub is seated in either of said eccentric bores andon said drum shaft so that said cylindrical drum extends within saidcylindrical housing in eccentric relationship to said cylindricalhousing, at least one end of said cylindrical drum is adapted to definea discharge end for treated fibre-liquid mixture, a baflie plate isassociated with said discharge end and mounted on the respective hub soas to be concentric with said cylindrical housing and to define togetherwith said cylindrical housing a circular ring gap narrowed in relationto said annular passage.

Conveniently, a mechanism may be provided and connected with the drumshaft for reciprocating the drum shaft by relatively short strokes inthe axial direction and during rotation thereof.

By a dressing device designed in this manner, the fibres will berepeatedly subjected to momentary increased pressure and thus still moreintensively fulled.

With certain kinds of asbestos, e.g. South African blue asbestos, thecomplete dressing of which is very difiicult owing to their particularfibre structure, faster disentangling of the fibre bunches and a betterdegree of dressing will be attained by the increased fulling. Damage tothe fibres owing to the action of mechanically applied pressure broughtabout by the eccentric rotation of the drum in the housing or by theaxially reciprocating motion of the drum is avoided because the fibresare acted upon by the pressure substantially transversely of thelongitudinal direction of the fibres so that the fibres, consequently,are not subjected to tension which might rupture the fibres.

The eccentric rotation and the oscillating motion of the drum result inthe best fulling efi'ect possible when both measures are applied incombination. In some cases, however, where it is the question ofdressing soft fibres, the application of eccentric rotation willgenerally be snfiicient.

To permit regulation of the transit time of the fibreliquid mixture inthe dressing device in accordance with the kind and quality of theasbestos material to be dressed, it is provided by a further developmentof the invention that an adjustable and lockable hinged trap may beincorporated in a recess in the bottom of the cylindrical housing in theregion of the discharge end portion of the horizontally arranged drumand serve as a regulating trap for draining off the treated fibre-liquidmixture or any desired portion thereof before this passes through thenarrowed circular ring gap. Conveniently, a discharge funnel may beconnected to the bottom of the housing to receive the quantities of thefibre-liquid mixture issuing through the open hinged trap as well asthrough the narrowed circular ring gap. Whereas with completely closedregulating trap the fibre-liquid mixture fed under high hydraulicpressure will issue through the narrowed annular gap defined by thebaffie plate, after having rotated several times together with therotating drum, the number of rotations of the fibre-liquid mixturewithin the housing can be reduced as desired by opening the hinged trapmore or less, thereby to adapt the duration of the fulling treatment ina simple manner to actual requirements so that the best degree possibleof opening the asbestos material is attainable at any time.

According to a preferred embodiment of the invention, the cylindricaldrum extends in a horizontal position within the cylindrical housing, abottom aperture is provided between the baffle plate and the cover ofthe housing, an opening is defined in the bottom of said housing in theregion covered by the discharge end of the drum, a hinged trap isincorporated in the opening so as to be adjustable and lockable, thehinged trap serving as a regulating trap for discharging a controllablequantity of the treated fibre-liquid mixture from the housing beforesaid quantity of treated fibre-liquid mixture passes through thecircular ring gap, and a discharge funnel is connected to the bottom ofthe housing at said discharge end of the drum and extends across thebottom aperture and the opening including the regulating trap.

For producing the reciprocating motion of the drum shaft, a suitablegearing may be incorporated and con nected in series with the motordriving the shaft. However,

since the drum shaft is not intended to effect such reciprocating motionupon each rotation thereof, the mechanism for reciprocating the drumshaft may include a flange seated on the drum shaft outside thecylindrical housing, an auxiliary shaft, two cam plates mounted on theauxiliary shaft in axially spaced relationship to each other, adouble-armed lever, a sliding member secured to one lever arm of thedouble-armed lever and guided between the cam plates; and a pair ofrollers provided on the outer lever arm of the double-armed lever andcontacting opposite end faces of the flange.

Since the crude asbestos material is to be dressed in a manner takingcare of the fibres in the best way possible,

it is advisable to provide either the cylindrical inner wall of thehousing or the cylindrically curved outer surface of the drum, whichconstitute cooperating friction surfaces, with a resilient coating ofrubber or rubber-like plastic. In order to produce in this case anintense friction in addition to the fulling effect, smallcircumferential grooves may be provided in the cooperating frictionsurfaces, for example in the cylindrical inner wall of the housing andin the rubber or plastic coating of the drum.

Two preferred embodiments of the invention will now be described by wayof example and with reference to the accompanying drawings, in which:

FIG. 1 is a vertical longitudinal central section through aschematically drawn device according to the invention;

FIG. 2 is a cross section taken on the line IIII of FIG. 1;

FIG. 3 is a partial longitudinal section, as in FIG. 1, through asimilar device having cooperating friction surfaces of a differentdesign;

FIG. 3a shows a detail of FIG. 3 on an enlarged scale; and

FIG. 3a is an enlarged sectional view taken generally along line IIIa ofFIG. 3, and more clearly illustrates the configuration of the rubbercoating carried by the drum and the generally complementaryconfiguration of the cylindrical housing.

FIG. 1 shows a dressing device according to the present invention,having a cylindrical housing 1, which is stationarily arranged onsupporting legs 28 on a horizontal position and closed at both ends bycovers 3 bolted thereto. A shaft 5, which is rotatably and axiallydisplaceably supported in two bearings 29 disposed at either end of thehousing 1, extends through central bores in the two covers 3. The shaftcarries a drum consisting of a cylindrical rigid drum shell 30 and oftwo circular end walls 32 provided with eccentric bores.

Hubs 31 are fitted in the eccentric bores in the end walls 32 of thedrum and fixed on the shaft 5 so that the drum occupies an eccentricposition in the housing 1 and a resilient coating 33 of rubber orplastic, which is applied to the curved outer surface of the drum shell30, is spaced along a certain apex line thereof, from the cylindricalinner wall of the housing 1 by the smallest distance of, for example,0.5 mm. and along the diametrically opposite apex line by the largestdistance of, for example, 5 mm., leaving between the drum shell 30 orits coating 33 and the inner cylindrical surface of the housing anannular passage of varying clearance for a fibre-liquid mixture to beforced therethrough during the dressing operation. Either end of thedrum is associated with a baflie plate 34 seated with a central middlebore on the respective hub 31. The baflle plates 34 are so dimensionedwith regard to their outer diameter that their rim edges terminate at asmall distance, for example, of 0.5 mm., from the cylindrical inner wallof the housing 1 and in conjunction with the inner wall of the housingdefine circular ring gaps 35 narrowed in relation to the annularpassage. When the drum shaft Sis rotated by a variable speed electricmotor, not shown, or another suitable driving motor, the cylindricaldrum shaft 30 will eccentrically rotate within the housing 1 so that thelargest clearance of the annular passage between the drum shell coating33 and the inner wall of the housing, which largest clearance in theposition of rotation of the drum plotted in FIGS. 1 and 2 is situated atthe upper apex line of the drum shell 30, and consequently also thesmallest clearance of the annular passage will continuously change theirposition during rotation of the drum.

The fibre-liquid mixture with the bunch-like adhered asbestos fibres tobe dressed will be forced under high hydraulic pressure by means of afeed pump, not shown, through a short feed pipe 36, which is arranged inthe central region of the housing 1 on an upwards facing portion of thewall of the housing, into the eccentric annular passage between theresilient drum coating 33 and the inner wall of the housing 1. Thefibre-liquid mixture will be forced in opposite directions through theannular passage and dragged along by the rotating drum in thecircumferential direction thereof. During rotation, the bunches offibres repeatedly reach the smallest passage clearance and arevigorously fulled between the resilient drum coating 33 and the rigidinner wall of the housing 1, with the result that the individual fibresare separated from the bunches of fibres and dressed without beingdamaged or ruptured.

Finally, the fibre-liquid mixture will pass together with the fibresseparated from the bunches through the narrow circular ring gaps 35 intochambers 37 defined between the baflie plates 34 and the covers 3 of thehousing 1, from which chambers 37 it is guided through funnels 39arranged under bottom apertures 38 of the housing 1 and through aconduit, not shown, to a further processing station or back into thedressing device for repeated treatment when, in the case of asbestosmaterial particularly hard to dress, during the firs-t transit throughthe dressing device the desired degree of dressing of the fibrousmaterial has not yet been attained. Stirring paddles 40 secured to thedrum shaft 5 within the chambers 37 take care that the fibre-liquidmixture is continuously discharged from the chambers 37.

When dressing asbestos material in which the individual fibres are nottightly adhered, it is possible to shorten the duration of treatment toa period of time sufficient for this material, in that the dischargethrottling brought about by the baffle plates 34 is partly or evencompletely eliminated. For this purpose, openings 41 are defined in thebottom portion of the housing 1 in the regions covered by the dischargeends of the drum and regulating traps 43 are hinged on axles 42 (FIG. 2)on the rear transverse edges, with respect to the direction of rotationof the drum, of the openings 41, and cover the openings 41 when being intheir closed positions. Either of the two traps 43 can be swung awayfrom the wall of the housing to the extent desired by operating anadjusting spindle 44, so that it clears with its side opposite the hingeaxle 42 a more or less large discharge gap in the wall of the housing 1,through which a controllable portion of the fibre-liquid mixture or, inthe case of completely opened traps 43 all of the supplied fibre-liquidmixture can bypass the narrow circular ring gap 35 and issue from thehousing 1 without having to pass through the circular ring gap 35. Byappropriately adjusting the regulating traps 43 it is possible to reducethe number of rotations, which the fibre-liquid mixture carries outtogether with the drum in the housing 1, and thus to accurately adjustin each case the transit time for the kind of asbestos material to bedressed.

As shown particularly in FIG. 2, each adjusting spindle 44 consists of athreaded rod 44a, which is rotatably but axially immovably mounted on arotatable sleeve 45 of a bracket 46 arranged outside the dischargefunnel 39, and of a threaded tube 44b, screwed on the threaded rod 44a,which tube 441) is led by means of rubber bellows in a liquid-tightmanner through an opening in one of the walls of the funnel 39, andpivoted to an eye 47 on the hinged trap 43. By turning the threaded rod44a fitted with a hand wheel so that the threaded tube 44b is screwedfurther on to the threaded rod 44a, the hinged trap 43 is moved awayfrom the wall of the housing 1, whereas by turning the threaded rod 44ain the opposite direction of rotation, the hinged trap 43 will be swungtowards the wall of the housing 1 and close the opening 41.

The discharge funnels 39 are so designed that they extend across thepermanent-1y open 'bottom aperture 38 situated under the chamber 37 inthe housing 1 and across the adjacent opening 41 with its regulatingtrap 43, to receive the quantities of the fibre-liquid mixture whichissue through the latter as well as, if desired, through the bottomaperture 38 via the baflie plate 34 and the chambers 37.

During its rotatory movement, the drum shaft 5 is adapted to performtogether with the drum mounted thereon an axially reciprocatingshort-stroke motion within the housing 1, which motion is so harmonizedwith the number of revolutions of the drum that the drum is pushed toand fro once upon a determined number of revolutions. The axiallyreciprocating motion of the drum shaft 5 is derived, as can be seen fromFIG. 1, from an auxiliary shaft 48 rotated by the motor driving the drumshaft 5, through the intermediary of a reduction gear, both not shown.Between two cam plates 49 fixed on the auxiliary shaft 48 there isguided a sliding member 50. The sliding member 50 is seated at the endof an arm of a double-arm lever 51 which is pivoted about a hinge bolt53 on a stationary bracket 52. On the two legs of a fork 54, which isdisposed on the other arm of the doublearmed lever 51, two convexlyturned rollers 55 are rotatably mounted to contact the two opposite endfaces of a flange 56 fixed on the drum shaft 5 for transmitting therocking movement of the double-armed lever 51, which is caused by thecam plates 49, to the drum shaft 5. The short-stroke reciprocation ofthe rotating drum shaft 5 assists the fulling of the fibre bunches to bedressed and, together with the eccentric rotation of the drum in thehousing 1, results in extraordinarily intensive fulling of the fibres.In this manner it is achieved to completely dress even such asbestosmaterial as has been hitherto particularly hard to dress. At the sametime, the resilient coating 33 of the rigid drum shell 30 ensurescareful treatment of the delicate fibres.

In the dressing device shown in FIG. 3, small circumferential grooves 57and 58 are defined in the inner wall of the housing 1 and in the outersurface of the resilient rubber or plastic coating 33 of the drum, i.e.,in the cooperating friction surfaces. For the sake of clearness, thegrooves 57 and '58 are represented excessively large in FIG. '3; inreality they have but a depth of about 3.0 mm. and a width of about 15.0mm. The grooves 57 and 58 cause an increased friction of the material tobe treated between the cooperating friction surfaces constituted by theresilient coating 33 of the drum shell 30 and the inner wall of thehousing 1, which again has a favourable effect on the fulling of thefibers.

I claim:

1. A device for dressing adhered asbestos natural state fibers separatedfrom the source rock and suspended in a liquid comprising a cylindricalhousing, a cover for each end of the housing having aligned drum shaftopenings therein, a drum shaft extending through said cover openings, acylindrical drum rotatably mounted on said drum shaft and rotatablewithin said housing and defining an annular passage between said drumand said housing, said passage being adapted to receive asbestos fiberssuspended in a liquid that is forced through said passage undercontrollable hydraulic pressure, the opposed faces of the housing anddrum being grooved, means for reciprocating the drum longitudinally ofthe housing for repeated bending of said fibers in constantly varyingdirections, a cylindrical end wall for each end of said cylindrical drumwith a bore therein, a hub in each 'bore through which the drum extends,each end of said cylindrical housing having a discharge aperture for thetreated fiber liquid mixture, a baffle plate in each end of the housingoutwardly of the end walls of the drum and mounted on said drum shaftinwardly of said discharge apertures for cooperation with saidcylindrical housing to form a circular ring gap narrowed in relation tosaid annular passage.

2. A device as set forth in claim 1, wherein the means for reciprocatingthe drum shaft includes mechanism connected with said drum shaft forreciprocating said drum shaft by relatively short strokes in the axialdirection and during rotation thereof.

3. A device as set forth in claim 1 wherein said cylindrical drumextends in a horizontal position within said cylindrical housing, therebeing an opening in the bottom of said housing adjacent each end thereofinwardly of the baflie plates in the region covered by each end of saiddrum, a hinged trap incorporated in said opening so as to be adjustableand lockable, said hinged trap serving as a regulating trap fordischarging a controllable quantity of said treated fiber liquid mixturefrom said housing before said quantity of treated fiber liquid mixturepasses through said circular ring gap and a discharge funnel connectedto the bottom of said housing at each end of said drum and extendingacross said discharge aperture and said opening including saidregulating trap.

4. A device as set forth in claim 1 wherein the mechanism forreciprocating said drum shaft includes a flange on said drum shaftexteriorly of one end of said cylindrical housing, an axillary shaft,two cam plates mounted on said auxiliary shaft in axially spacedrelationship to each other, a double-armed lever, a sliding membersecured to one lever arm of said double-armed lever and guided betweensaid cam plates, and a pair of rollers provided on the, other lever armof said double-armed lever and contacting opposite end faces of saidflange.

5. A device as set forth in claim 1 wherein the inner cylindricalsurface of said housing and the outer cylindrical surface of said drumhave cooperating friction surfaces.

6. A device as set forth in claim 5 wherein one of said cooperatingfriction surfaces is provided with a coating of resilient material.

7. A device as set forth in claim 6 wherein said resilient material isrubber.

8. A device as set forth in claim 6 wherein said resilient material isplastic.

References Cited UNITED STATES PATENTS 7,072 2/1850 Jackson et .al.19100 773,479 10/1904 Cornell 241205 X 838,370 11/1906 Belt et a1.241221 X 1,799,685 4/ 193 1 Gminder. 1,971,335 8/ 1934 Benner et a1.241205 1,980,589 11/1934 Acree 241-221 X 2,173,975 9/1939 Lyons 241-21 X2,309,376 1/1943 Avery 241254 3,221,999 12/1965 Cumpston 241-255 X3,228,067 1/1966 Strang et a1. 1966 FOREIGN PATENTS 183,631 10/ 1955Austria. 1,083,767 6/ 1954 France.

317,981 8/ 1929 Great Britain.

680,576 10/ 1952 Great Britain.

MERVIN STEIN, Primary Examiner. D. NEWTON, Assistant Examiner,

